1.(2018·江苏高考，32)Try to understand what's actually happening instead of acting on the ________ (assume) you've made.
答案：assumption 由空前的定冠词the和空后的made可知，这里应填入名词作made的宾语，故答案为assumption。
2．(2018·全国卷Ⅱ，66)This switch has decreased ________ (pollute) in the country's major lakes and reservoirs and made drinking water safer for people.
答案：pollution 谓语动词has decreased后应接名词作宾语，故填pollution。
3．(2018·全国卷Ⅲ，66)I'm a ________ (science) who studies animals such as apes and monkeys.
答案：scientist 不定冠词a后应跟单数名词，故填scientist。
4．(2017·全国卷Ⅱ，69)This development was only possible with the ________ (introduce) of electricpowered engines and lifts.
答案：introduction 由空格前的定冠词the可知，其后应接名词作介词with的宾语。
